Comparing cultures can be a good way of working out what you want to put in your fictional world. Perspectives are different. Some cultures are very "now"orientated, others are more laid back so what would you have in your creation? How does time work in your world?
What kind of geography would you have? There shouldn't be just one kind, as there isn't here on Earth, but what species lives where and how have they adapted to make the most of their environment? Does the climate vary? Has it been damaged by pollution (and if so how)?
Asking questions is a great way to work out what you want to create. And asking further questions is a good way of testing whether those initial ideas (a) work at all and (b) are they strong enough to "carry" a novel?